Enjoying fragrance is unique because it doesn’t have the same tangible impact as other pleasures. Our bodies don’t gain weight and the plant is not used up or destroyed when we smell it. The Sages felt that such a special pleasure calls for a special blessing: “What does the soul enjoy? … Scents” (Berachot 43).

The Sages instituted three types of blessings: Borei minei besamim, borei atzei besamim, borei Isvei besamim. Which blessing do we say?

A plant is classified as a tree when its trunk lives for several years and its branches produce leaves again and again. On such plants we say the blessing, borei atzei besamim, “Creator of fragrant trees.”

On plants that die each year and need to be planted again, or have a main trunk that withers and new stems emerges from the root, we say, borei isbei besamim, “Creator of fragrant grasses.”

For herbs with questionable status, we say, borei minei besamim, “Creator of fragrant species.” This blessing covers both fragrant trees and fragrant grasses.

Look at the signs and see which plants are annual and which are perennial. If you look closely, you’ll even find some of the herbs used for the ketoret, the incense offered in the Holy Temple.